/*
 *  Copyright 2013 National Institute of Advanced Industrial Science and Technology
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.sss.common.io;

import java.io.IOException;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.sss.common.CanceledException;
import org.sss.common.DataReceiver;
import org.sss.common.ErrorDataReceiverException;
import org.sss.mapreduce.Configuration;
import org.sss.mapreduce.GroupID;
import org.sss.mapreduce.SssException;
import org.sss.mapreduce.StorageNode;

/**
 * .
 * NOTE: access int only this module.
 */
abstract class AbstractFlatDataReader extends AbstractDataReader {
  private static Logger logger = LoggerFactory.getLogger(AbstractFlatDataReader.class);

  protected final StorageNode node;
  protected final int subhash;
  protected final DataReceiver<List<byte[]>> next;

  public AbstractFlatDataReader(Configuration conf, StorageNode node,
    GroupID gid, int subhash, DataReceiver<List<byte[]>> next) throws SssException {
    super(gid, conf);
    this.node    = node;
    this.subhash = subhash;
    this.next    = next;
  }

  @Override
  public void run() {
    logger.debug("READ GroupID {}", getSource());
    try {
      issueCommands(IOThread.currentThread());
    } catch (ErrorDataReceiverException e) {
      logger.debug("Ignores ErrorDataReceiverException", e);
    } catch (CanceledException e) {
      next.setError(e);
    } catch (Throwable e) {
      logger.error("", e);
      next.setError(e);
    }
  }

  protected abstract void issueCommands(IOThread iot) throws SssException, IOException;
}
